Audio FIFO Buffer

Typedefs
typedef struct AVAudioFifo	AVAudioFifo
	Context for an Audio FIFO Buffer.

Functions
void	av_audio_fifo_free (AVAudioFifo *af)
	Free an AVAudioFifo.
AVAudioFifo *	av_audio_fifo_alloc (enum AVSampleFormat sample_fmt, int channels, int nb_samples)
	Allocate an AVAudioFifo.
av_warn_unused_result int	av_audio_fifo_realloc (AVAudioFifo *af, int nb_samples)
	Reallocate an AVAudioFifo.
int	av_audio_fifo_write (AVAudioFifo *af, void *const *data, int nb_samples)
	Write data to an AVAudioFifo.
int	av_audio_fifo_peek (const AVAudioFifo *af, void *const *data, int nb_samples)
	Peek data from an AVAudioFifo.
int	av_audio_fifo_peek_at (const AVAudioFifo *af, void *const *data, int nb_samples, int offset)
	Peek data from an AVAudioFifo.
int	av_audio_fifo_read (AVAudioFifo *af, void *const *data, int nb_samples)
	Read data from an AVAudioFifo.
int	av_audio_fifo_drain (AVAudioFifo *af, int nb_samples)
	Drain data from an AVAudioFifo.
void	av_audio_fifo_reset (AVAudioFifo *af)
	Reset the AVAudioFifo buffer.
int	av_audio_fifo_size (AVAudioFifo *af)
	Get the current number of samples in the AVAudioFifo available for reading.
int	av_audio_fifo_space (AVAudioFifo *af)
	Get the current number of samples in the AVAudioFifo available for writing.

Detailed Description

Typedef Documentation

AVAudioFifo

typedef struct AVAudioFifo AVAudioFifo

Context for an Audio FIFO Buffer.

• Operates at the sample level rather than the byte level.
• Supports multiple channels with either planar or packed sample format.
• Automatic reallocation when writing to a full buffer.

Definition at line 48 of file audio_fifo.h.

Function Documentation

av_audio_fifo_free()

void av_audio_fifo_free

(

AVAudioFifo *

af

)

Free an AVAudioFifo.

Parameters

af	AVAudioFifo to free

Examples

transcode_aac.c.

Referenced by main().

av_audio_fifo_alloc()

AVAudioFifo * av_audio_fifo_alloc	(	enum AVSampleFormat	sample_fmt,
		int	channels,
		int	nb_samples
	)

Allocate an AVAudioFifo.

Parameters

sample_fmt	sample format
channels	number of channels
nb_samples	initial allocation size, in samples

Returns

newly allocated AVAudioFifo, or NULL on error

Examples

transcode_aac.c.

Referenced by init_fifo().

av_audio_fifo_realloc()

av_warn_unused_result int av_audio_fifo_realloc	(	AVAudioFifo *	af,
		int	nb_samples
	)

Reallocate an AVAudioFifo.

Parameters

af	AVAudioFifo to reallocate
nb_samples	new allocation size, in samples

Returns

0 if OK, or negative AVERROR code on failure

Examples

transcode_aac.c.

Referenced by add_samples_to_fifo().

av_audio_fifo_write()

int av_audio_fifo_write	(	AVAudioFifo *	af,
		void *const *	data,
		int	nb_samples
	)

Write data to an AVAudioFifo.

The AVAudioFifo will be reallocated automatically if the available space is less than nb_samples.

See also

enum AVSampleFormat The documentation for AVSampleFormat describes the data layout.

Parameters

af	AVAudioFifo to write to
data	audio data plane pointers
nb_samples	number of samples to write

Returns

number of samples actually written, or negative AVERROR code on failure. If successful, the number of samples actually written will always be nb_samples.

Examples

transcode_aac.c.

Referenced by add_samples_to_fifo().

av_audio_fifo_peek()

int av_audio_fifo_peek	(	const AVAudioFifo *	af,
		void *const *	data,
		int	nb_samples
	)

Peek data from an AVAudioFifo.

See also

enum AVSampleFormat The documentation for AVSampleFormat describes the data layout.

Parameters

af	AVAudioFifo to read from
data	audio data plane pointers
nb_samples	number of samples to peek

Returns

number of samples actually peek, or negative AVERROR code on failure. The number of samples actually peek will not be greater than nb_samples, and will only be less than nb_samples if av_audio_fifo_size is less than nb_samples.

av_audio_fifo_peek_at()

int av_audio_fifo_peek_at	(	const AVAudioFifo *	af,
		void *const *	data,
		int	nb_samples,
		int	offset
	)

Peek data from an AVAudioFifo.

See also

enum AVSampleFormat The documentation for AVSampleFormat describes the data layout.

Parameters

af	AVAudioFifo to read from
data	audio data plane pointers
nb_samples	number of samples to peek
offset	offset from current read position

Returns

number of samples actually peek, or negative AVERROR code on failure. The number of samples actually peek will not be greater than nb_samples, and will only be less than nb_samples if av_audio_fifo_size is less than nb_samples.

av_audio_fifo_read()

int av_audio_fifo_read	(	AVAudioFifo *	af,
		void *const *	data,
		int	nb_samples
	)

Read data from an AVAudioFifo.

See also

enum AVSampleFormat The documentation for AVSampleFormat describes the data layout.

Parameters

af	AVAudioFifo to read from
data	audio data plane pointers
nb_samples	number of samples to read

Returns

number of samples actually read, or negative AVERROR code on failure. The number of samples actually read will not be greater than nb_samples, and will only be less than nb_samples if av_audio_fifo_size is less than nb_samples.

Examples

transcode_aac.c.

Referenced by load_encode_and_write().

av_audio_fifo_drain()

int av_audio_fifo_drain	(	AVAudioFifo *	af,
		int	nb_samples
	)

Drain data from an AVAudioFifo.

Removes the data without reading it.

Parameters

af	AVAudioFifo to drain
nb_samples	number of samples to drain

Returns

0 if OK, or negative AVERROR code on failure

av_audio_fifo_reset()

void av_audio_fifo_reset

(

AVAudioFifo *

af

)

Reset the AVAudioFifo buffer.

This empties all data in the buffer.

Parameters

af	AVAudioFifo to reset

av_audio_fifo_size()

int av_audio_fifo_size

(

AVAudioFifo *

af

)

Get the current number of samples in the AVAudioFifo available for reading.

Parameters

af	the AVAudioFifo to query

Returns

number of samples available for reading

Examples

transcode_aac.c.

Referenced by add_samples_to_fifo(), load_encode_and_write(), and main().

av_audio_fifo_space()

int av_audio_fifo_space

(

AVAudioFifo *

af

)

Get the current number of samples in the AVAudioFifo available for writing.

Parameters

af	the AVAudioFifo to query

Returns

number of samples available for writing